Case study: multiple sclerosis

Multiple sclerosis (MS) is a condition that affects the central nervous system. It is relatively rare with about 120,000 in the whole of the UK having a diagnosis. The symptoms that individuals with MS show are very variable. This is because any part of their central nervous system may be affected by the disease process and, as we have met, some functions are localised. So, the location of the pathology in any one individual will determine the symptoms that they have.

Your task:

• Look up the symptoms that are commonly seen in MS patients. Relate these to the regions of the brain we have met earlier in this week.

Although our understanding of the causes of MS is incomplete, the evidence suggests that the glial cells are the primary pathological target. We met glial cells in general terms in Weeks 1 and 2. There are a number of types of glia in the human nervous system but the ones that are linked to MS are those that wrap around the axons of neurones in the central nervous system.

Your task:

• What do the glia that wrap around axons produce to aid the conduction of electrical signals along the axon?

• Which type of glia performs this function in the central nervous system?